to buy the equipment at full retail price as if it is fresh out of the box. I don't want fingerprints on it, I don't want the menus to be set, I don't want two or three thousand actuations on the shutter count, and I definitely don't want to have to guess whether the "new" equipment has been mishandled regardless of whether it has been kept on or off the premises.

A seal on the box would certainly take care of my concerns. If you want to get the experience of handling and trying out the equipment, then how about renting it instead of expecting the brick and mortar operators to crack their boxes or, worse yet, buying it off the internet and returning it for some esoteric reason.